Motorcycle Repair: 81 Virago, yamaha virago xv750, thanks in advance

Question
Chris,

I bought an '81 Yamaha Virago XV750 a few months ago.  It didn't run when I bought it, took it to a mechanic that said he could get it going but he took too long and I figured I'd fix it myself.  It had sat for six years and the owner thought that something was wrong with the electrical system.  The mechanic "supposedly" fixed that.  I've had the carbs off twice myself to go through and replace an intake boot.  The inside of the carbs look clean (mechanic cleaned three times)and free of defect from what my inexperienced eyes can tell... probably need to be tuned though.  The bike will start right up if I haven't tried to in a few but will stall 2 or 3 seconds afterwards.  After it stalls, it won't start again until it has sat.  The rub is... I can start it one of two ways, # one-spray some starting fluid into the intake and keep it running by manually choking it and not until really hot (probably too hot) will it run on its own; # two- I know your not supposed to do this, but when I jump from my car it starts and'll run for awhile but idles really slowly, only the rear cyclinder firing (hot to touch).

I'm not sure what the problem is or how to diagnos it at this point.  Carbs or electrical... both?

Thanks in advance,

Dan  

Answer
Hi Dan.
 You could still have a short in the ignition system.  Not all shorts are easy, or even sometimes possible to find.  Particularly intermittent shorts.  What you have described sounds exactly like an itermittent short.  Try rigging a bypass for the wiring from power to the offending ignition circuit and see if it stays running.

Good luck.
FALCON